An existing web system assumes that one user logs in from one web browser. Recently, however, with increase in the size of a projector and a liquid crystal monitor and improvement of screen sharing tools and the like, a use form in which multiple users share one web screen and perform reference and operations is also practiced. For example, in an environment (e.g., a web system, a general computer system, etc.) in which an external USB keyboard or a mouse is connected to a notebook PC connected to a projector, such a use form can be provided.